Nicotinamide n-Oxide Attenuates HSV-1-Induced Microglial Inflammation through Sirtuin-1/NF-κB Signaling.

HSV-1 is a typical neurotropic virus that infects the brain and causes keratitis, cold sores, and occasionally, acute herpes simplex encephalitis (HSE). The large amount of proinflammatory cytokines induced by HSV-1 infection is an important cause of neurotoxicity in the central nervous system (CNS). Microglia, as resident macrophages in CNS, are the first line of defense against neurotropic virus infection. Inhibiting the excessive production of inflammatory cytokines in overactivated microglia is a crucial strategy for the treatment of HSE. In the present study, we investigated the effect of nicotinamide n-oxide (NAMO), a metabolite mainly produced by gut microbe, on HSV-1-induced microglial inflammation and HSE. We found that NAMO significantly inhibits the production of cytokines induced by HSV-1 infection of microglia, such as IL-1ß, IL-6, and TNF-α. In addition, NAMO promotes the transition of microglia from the pro-inflammatory M1 type to the anti-inflammatory M2 type. More detailed studies revealed that NAMO enhances the expression of Sirtuin-1 and its deacetylase enzymatic activity, which in turn deacetylates the p65 subunit to inhibit NF-κB signaling, resulting in reduced inflammatory response and ameliorated HSE pathology. Therefore, Sirtuin-1/NF-κB axis may be promising therapeutic targets against HSV-1 infection-related diseases including HSE.

Hope During the COVID-19 Epidemic Decreased Anxiety and Depression Symptoms Mediated by Perceived Stress: Coping Style Differences Among Patients with COVID-19.

OBJECTIVE: This study aimed to investigate whether perceived stress mediated the relationship between hope and anxiety/depression symptoms among patients with COVID-19 during the epidemic. In addition, the potential moderating effect of coping styles was examined. METHODS: From February 26 to March 10, 2020, patients with COVID-19 were asked to complete a questionnaire online, which included demographic characteristics, as well as the SCL-90-Anxiety, SCL-90-Depression, Chinese Perceived Stress Scale (CPSS), Herth Hope Index (HHI), and Trait Coping Style Questionnaire (TCSQ). Hierarchical linear regression was performed to explore independent factors of anxiety/depression. A multi-group structural equation modeling with the collected data from patients in the Negative Coping style (NC) group and Positive Coping style (PC) group was used to test the hypothesized mechanism. RESULTS: In total, 382 valid questionnaires of patients were obtained, including 96 from NC patients and 286 from PC patients. In the hierarchical linear regression, hope and perceived stress were independent risk factors for both anxiety and depression in the total sample and PC group. However, hope was not independently related to anxiety/depression in the NC group. As hypothesized, the hope of patients had significant and negative indirect effects on both anxiety and depression that were mediated by perceived stress, However, the direct effect from stress on anxiety and depression was stronger for NC patients than for PC patients. Besides, hope had significant direct effects on anxiety/depression in PC patients, but not in NC patients. CONCLUSION: During the COVID-19 epidemic, perceived stress could mediate the relationship between hope and anxiety/depression symptoms among COVID-19 patients, with coping style moderating this cultivation process.

The roles of inactivated vaccines in older patients with infection of Delta variant in Nanjing, China.

BACKGROUND: The coronavirus disease 2019 (COVID-19) is spreading around the world. The COVID-19 vaccines may improve concerns about the pandemic. However, the roles of inactivated vaccines in older patients (aged ≥60 years) with infection of Delta variant were less studied. METHODS: We classified the older patients with infection of Delta variant into three groups based on the vaccination status: no vaccination (group A, n = 113), one dose of vaccination (group B, n = 46), and two doses of vaccination (group C, n = 22). Two inactivated COVID-19 vaccines (BBIBP-CorV or CoronaVac) were evaluated in this study. The demographic data, laboratory parameters, and clinical severity were recorded. RESULTS: A total of 181 older patients with infection of Delta variant were enrolled. 111 (61.3%) patients had one or more co-morbidities. The days of "turn negative" and hospital stay in Group C were lower than those in the other groups (P < 0.05). The incidences of multiple organ dysfunction syndrome (MODS), septic shock, acute respiratory distress syndrome (ARDS), acute kidney injury, and cardiac injury in Group A were higher than those in the other groups (P < 0.05). The MV-free days and ICU-free days during 28 days in Group A were also lower than those in the other groups (P < 0.05). In patients with co-morbidities, vaccinated cases had lower incidences of MODS (P = 0.015), septic shock (P = 0.015), and ARDS (P = 0.008). CONCLUSIONS: The inactivated COVID-19 vaccines were effective in improving the clinical severity of older patients with infection of Delta variant.

SARS-CoV-2 infection activates a subset of intrinsic pathways to inhibit type I interferons in vitro and in vivo.

SARS-CoV-2 infection poses a global challenge to human health. Upon viral infection, host cells initiate the innate antiviral response, which primarily involves type I interferons (I-IFNs), to enable rapid elimination of the invading virus. Previous studies revealed that SARS-CoV-2 infection limits the expression of I-IFNs in vitro and in vivo, but the underlying mechanism remains incompletely elucidated. In the present study, we performed data mining and longitudinal data analysis using SARS-CoV-2-infected normal human bronchial epithelial (NHBE) cells and ferrets, and the results confirmed the strong inhibitory effect of SARS-CoV-2 on the induction of I-IFNs. Moreover, we identified genes that are negatively correlated with IFNB1 expression in vitro and in vivo based on Pearson correlation analysis. We found that SARS-CoV-2 activates numerous intrinsic pathways, such as the circadian rhythm, phosphatidylinositol signaling system, peroxisome, and TNF signaling pathways, to inhibit I-IFNs. These intrinsic inhibitory pathways jointly facilitate the successful immune evasion of SARS-CoV-2. Our study elucidates the underlying mechanism by which SARS-CoV-2 evades the host innate antiviral response in vitro and in vivo, providing theoretical evidence for targeting these immune evasion-associated pathways to combat SARS-CoV-2 infection.

Progress in the Research and Development of Anti-COVID-19 Drugs.

The outbreaks of COVID-19 due to SARS-CoV-2 has caused serious physical and psychological damage to global human health. COVID-19 spread rapidly around the world in a short time. Confronted with such a highly infectious respiratory disease, the research and development of anti-COVID-19 drugs became an urgent work due to the lack of specific drugs for the treatment of COVID-19. Nevertheless, several existing drugs are available to relieve the clinical symptoms of COVID-19. We reviewed information on selected anti-SARS-CoV-2 candidate therapeutic agents published until June 2, 2020. We also discussed the strategies of the development of anti-COVID-19 drugs in the future. Our review provides a novel insight into the future development of a safer, efficient, and toxic-less anti-COVID-19 drug.

A comprehensive investigation of the mRNA and protein level of ACE2, the putative receptor of SARS-CoV-2, in human tissues and blood cells.

The outbreak of pneumonia caused by SARS-CoV-2 posed a great threat to global human health, which urgently requires us to understand comprehensively the mechanism of SARS-CoV-2 infection. Angiotensin-converting enzyme 2 (ACE2) was identified as a functional receptor for SARS-CoV-2, distribution of which may indicate the risk of different human organs vulnerable to SARS-CoV-2 infection. Previous studies investigating the distribution of ACE2 mRNA in human tissues only involved a limited size of the samples and a lack of determination for ACE2 protein. Given the heterogeneity among humans, the datasets covering more tissues with a larger size of samples should be analyzed. Indeed, ACE2 is a membrane and secreted protein, while the expression of ACE2 in blood and common blood cells remains unknown. Herein, the proteomic data in HIPED and the antibody-based immunochemistry result in HPA were collected to analyze the distribution of ACE2 protein in human tissues. The bulk RNA-seq profiles from three separate public datasets including HPA tissue Atlas, GTEx, and FANTOM5 CAGE were also obtained to determine the expression of ACE2 in human tissues. Moreover, the abundance of ACE2 in human blood and blood cells was determined by analyzing the data in the PeptideAtlas and the HPA Blood Atlas. We found that the mRNA expression cannot reflect the abundance of ACE2 factor due to the strong differences between mRNA and protein quantities of ACE2 within and across tissues. Our results suggested that ACE2 protein is mainly expressed in the small intestine, kidney, gallbladder, and testis, while the abundance of which in brain-associated tissues and blood common cells is low. HIPED revealed enrichment of ACE2 protein in the placenta and ovary despite a low mRNA level. Further, human secretome shows that the average concentration of ACE2 protein in the plasma of males is higher than those in females. Our research will be beneficial for understanding the transmission routes and sex-based differences in susceptibility of SARS-CoV-2 infection.

The neutrophil-to-lymphocyte ratio determines clinical efficacy of corticosteroids therapy in patients with COVID-19 (preprint)

Preliminary results from the RECOVERY trial indicated that dexamethasone usage markedly reduced death rate in COVID-19 patients receiving invasive mechanical ventilation. However, the overall reduction for the entire patient cohort in that trial was much more modest, indicating highly variable effects of corticosteroid usage among COVID-19 patients. While steroid treatment is known to have both clinical efficacy and detrimental adverse-effects, defining a clinic parameter that could guide the beneficial corticosteroid usage for treating COVID-19 remains an elusive, urgent, and critical unmet need in COVID-19 therapy. Here, we undertook a multicentered retrospective study on a cohort of 12,862 confirmed COVID-19 cases from 21 hospitals in Hubei Province, China, including 3,254 received corticosteroid treatment and 9,608 received usual care without corticosteroid. We uncovered that the clinical benefits of corticosteroid use were closely associated with the neutrophil-to-lymphocyte ratio (NLR) measured at admission. Among participants with NLR > 6.12 at admission, corticosteroid treatment was significantly associated with a lower risk of 60-day all-cause mortality of COVID-19 based on both Cox model with time-varying exposure and Marginal Structural Model. However, in patients with NLR ≤ 6.12 at admission, corticosteroid treatment was no longer associated with reduced risk of all-cause death, but rather with increased risks of severe adverse effects, particularly in hyperglycemia and infection. In diabetic patients with COVID-19, corticosteroid treatment was associated with increased glycemia, but not with a higher risk of 60-day mortality. Therefore, our study has uncovered NLR as a clinical indicator to stratify COVID-19 patients in their response to corticosteroid therapy. This finding may assist clinical evaluation and future randomized controlled trials to establish proper guidelines for corticosteroid therapy in COVID-19 patients.